With the development of mobile communication networks and the advancement of terminal specifications, mobile communication terminals have become the essential belongings of people today beyond the level of conventional simple communication devices or information provision devices, and are evolving into total entertainment devices.
In particular, recently, cloud computing technologies that enable users to access a server connected to the Internet using various terminals anywhere and at any time and then use storage provided by the server or use various applications are widely used. Among these technologies, a cloud storage service (CSS) refers to a service that is capable of configuring physically separate pieces of storage equipment into a single piece of logical storage and allocating and providing a storage space on a capacity basis in real time when a user requests the storage space.
In this cloud storage service, storage spaces are allocated to authorized users, and the users use the cloud storage service by paying usage fees corresponding to the allocated storage spaces.
However, storage spaces used by users are limited spaces. Accordingly, efficient storage space control is required to allocate the storage spaces to numerous users and collect the storage spaces.
Accordingly, there are needs for not only the development of a technology capable of efficiently using storage spaces based on cloud computing and a technology capable of smoothly performing data interoperability between terminals but also the development of a technology capable of providing new additional services to users using the technologies.